B(E2;0(g.s)(+).-> 2(1)(+)) in Si-26 and mirror symmetry in the A=26 system- art. no. 057304

We have measured the electromagnetic matrix element B(E2;0(g.s.)(+)-->2(1)( +)) in the radioactive nucleus Si-26 using the method of intermediate energ y Coulomb excitation. Our result, B(E2;0(g.s.)(+) --> 2(1)(+)) = 336(33) e( 2) fm(4), resolves a conflict in previous measurements of this matrix eleme nt. In addition, the present measurement allows us to determine M-n/M-p for Mg-26 using the mirror nucleus method. The mirror method result of M-n/M-p = 1.05(6) is consistent with the most recent pion scattering results and i s near the simple collective model expectation.